Grilled Chicken Burgers

• 1 chicken breast, sliced in half
• 1 tbsp extra virgin olive oil
• 1 tsp chilli powder
• 2 tsp garlic powder
• 2 tsp cumin
• 2 tsp oregano
• 2 wholemeal bread rolls
• 1 baby cos lettuce
• 1 tomato, sliced
• 1 avocado, mashed
• .25 red onion, thinly sliced